United States v. Microsoft: Department of Justice and 20 states file an antitrust case against Microsoft

United States of America v. Microsoft Corporation, 253 F.3d 34 (D.C. Cir. 2001), was a landmark American antitrust law case at the United States Court of Appeals for the District of Columbia Circuit. The U.S. government accused Microsoft of illegally monopolizing the web browser market for Windows, primarily through the legal and technical restrictions it put on the abilities of PC manufacturers (OEMs) and users to uninstall Internet Explorer and use other programs such as Netscape and Java.

At the initial trial which began in 1998, the United States District Court for the District of Columbia ruled that Microsoft's actions constituted unlawful monopolization under Section 2 of the Sherman Antitrust Act of 1890, but the U.S. Court of Appeals for the D.C.